Mechanisms for dispensing unit doses of materials



' Aug. 5.1969 R. H. o. F, LEE ETAL 5 MECHANISMS FOR DISPENSING UNITDOSES OF MATERIALS (fled Au: 15. 1967 2 Sheets-Sheet 1 PT /0 I 31 *4.ayi

Inventor;

A tlorney Aug. 5, 1969 R-"H. D. F. LEE ETAI.

"ECHANISMS FOR DISPENSING UNIT'DOSES OF MATERIALS Filed Aug. 15. 19s? 2Sheets-Sheet 2 tan 1 16mm 644w Ame P24433 26! A llorneys United StatesPatent US. Cl. 222-219 7 Claims ABSTRACT OF THE DISCLOSURE Thisinvention particularly provides a mechanism for rapidly dispensing unitdoses of medicaments, especially to animals such as sheep, wherein themedicament is forced by gas pressure out of a container into themechanism which includes a rotatable plug with a bore therein in which amember is movable between stop means which define a unit dose. The inletconduit has two inner ports and two corresponding inner ports areprovided for the outlet conduit so that the plug can be oscillated toregister the bore with one corresponding pair of ports of the inlet andoutlet conduits and the other pair successively, the piston being causedat each registration to move toWards the outlet conduit and dispense aunit dose from the one end of the bore while taking in another unit doseat the other end of the bore.

Background of invention The invention particularly concerns the field ofmechanisms which can be used to dispense unit doses of medicaments toanimals such as sheep either orally or by injection. While solidmaterial, e.g. in pill form can be dispensed orally by quite simplemechanisms it is preferable to deliver liquid materials in particularfrom a large source which thus requires the use of a more complicatedmechanism which can firstly meter and secondly dispense unit doses ofthe material. It is becoming increasingly important in veterinarymedicine to provide a cheap, simple, yet effective mechanism of thisform which can dispense unit doses of medicaments rapidly with a fastturnover so that many animals can be effectively treated in a relativelyshort time.

Summary of the invention It is an object of this invention to provide amechanism which will readily and eificiently provide small measureddoses of materials.

It is a further object of this invention to provide a mechanism whichwill render possible the dispensing of modern medicaments in the verysmall doses consistent with their greater potency, at a fairly rapidrate, and which mechanism will also make possible a reduction in theamount of inert material accompanying the active ingredient(s)Accordingly the invention, in one aspect, provides a mechanism fordispensing unit doses of a liquid, semiliquid or gaseous material,comprising a housing in corporating a rotatable plug, the plug defininga through bore in which measuring means is movable between stop means inthe bore to define a unit dose of said material, the housing alsodefining an inlet conduit and an outlet conduit each having at least twoinner ports, each inner port of the inlet conduit being co-axial with acorresponding inner port of the outlet conduit so as to be able toregister with the two ends of said bore simultaneously, the inletconduit having an outer port to which may be detachably sealed areservoir which contains the material Patented Aug. 5, 1969 to bedispensed and which incorporates an internal pressure source acting onsaid material and the outlet conduit having an outer port to which adischarge tube may be detachably sealed, the mechanism furtherincorporating operating means enabling said plug to be rotated so thatone end of said bore will be moved out of registration with an innerport of said inlet conduit into registration with an inner port of saidoutlet conduit and vice versa.

The construction of this mechanism is such that incoming material forcesthe measuring means to the stop means farthest away from the inletconduit thus locating a unit dose of the material in the bore on theside of the measuring means nearest an inner port of the inlet con duitand simultaneously displacing an equal dose from the bore on the otherside of the measuring means towards an inner port of the outlet conduit.

The main parts of the mechanism are the plug and its associated housing.To prevent leakage of material in its passage from inlet conduit to plugbore and from plug bore to outlet conduit, it is desirable to taper theplug Walls and complement the walls of the cavity in the housing inwhich the plug is located.

The displacement of the movable measuring means between the stop meansdefines the unit dose of the material to be contained within the plugbore. In operation, the plug is located such that one end of the plugbore is continuous with an inner port of the inlet conduit with themeasuring means as far towards the inlet conduit as its stop means willpermit. Material is advanced under pressure from the detachablereservoir into the inlet conduit through the outer port thereof whenceit travels to emerge through an inner port of the inlet conduit. Thematerial then meets the measuring means which is displaced along thebore to the other stop means whereby only a dose of material is causedto pass into the plug bore. The plug is then rotated to a secondposition in which the other wall of the measuring means faces an otherinner port of the inlet conduit, the unit dose of material containedwithin the bore being presented to an inner port of the outlet conduit.As more material is forced through the inlet conduit under pressure todefine a new unit dose of material, the measuring means is forced alongthe bore to the other stop means causing the existing measured dose onthe other side of the measuring means to be displaced to the outletconduit. In operation, therefore, with each rotation of the plug, itsbore receives a new unit dose of material from the inlet conduit anddisplaces the preceding unit dose to the outlet conduit.

When the mechanism is first put to use and the bore contains nomaterial, the incoming material under pressure will of course displaceonly air or any other fluid from the bore. Following rotation of theplug, the first dose will then be displaced along the bore towards theouter port of the outlet conduit. This dose may or may not be dischargedthrough this outer port and will lie in the part of bore beyond the stopmeans or in the outlet conduit or in both, depending on the size of thedose, the position of the stop means and the dimensions of the bore andthe outlet conduit. Successive doses will fill any space between thestop means and the outlet conduit, until the displacement of the nextunit dose by the measuring means by virtue of the pressure in thereservoir, displaces an equal dose of material from the outer port ofthe outlet conduit at each subsequent load/discharge position of theplug. In practice, therefore, the space between the stop means and theoutlet conduit will be filled with material while the mechanism is beingoperated.

In a simple embodiment, the movable measuring means within the plug boreis a free piston and the limits of its displacement within the bore aredefined by any appropriate stop means, for example, circlips. Inoperation, the

plug is rotated such that the free piston abuts a circlip facing aninner port of the inlet conduit, material is forced in under pressure asdescribed, the plug is rotated through the angle between adjacent innerports so that the measured dose is presented to an inner port of theoutlet conduit and that dose is displaced along the bore and under thepressure of the incoming dose through the other inner port of the inletconduit.

Another more sophisticated, embodiment is one in which instead of a freepiston there is a diaphragm held peripherally in the bore by anyconvenient means, for example, a screwed ferrule. In operation, thediaphragm is displaced under pressure of the incoming material along thebore to a limit determined by stop means. These may comprise a wire meshor perforated metal pressings of hemi-spherical shape on each side ofthe diaphragm, and act not only as stop means for determining the limitsof displacement of the diaphragm, but also as support for the diaphragm.The limits of displacement of the diaphragm determine the size of thedose.

The simplest and preferred arrangement of the device of this inventionhas two sets of inner ports. Each inner port of the outlet conduit ofone co-axial set of ports is most preferably adjacent to the inner portof the inlet conduit of the other co-axial set, so that the plug needonly be oscillated through a small angle from one load/dischargeposition to the next. The location of such adjacent ports in the housingshould be such as not to allow the bore to register simultaneously withmore than one set of ports during oscillation of the plug intermediateone set of ports and the next.

Conveniently a discharge spout is sealed to the outer port of the outletconduit, which spout is of short length so that the friction does notunduly impede the movement of the material. A cap may be provided forthe discharge spout to prevent the medicament therein from drying out.

As previously mentioned, this invention is not limited to guns fororally administering dispensed doses of medicaments to animals. Oneother possible use in human or veterinary medicine is in administeringmedicaments and the like by injection and in such a case, the dischargespout will take the form of a mount for a hypodermic needle.

Rotation of the plug within the housing may be achieved manually,mechanically or electrically, by any convenient means. In a simple form,the plug is provided with a gear wheel co-operating with an axial rackwhereby the plug may be rotated from one load/discharge position to thenext. Stops will be provided to limit the arc of rotation to anappropriate value. It will be appreciated that there is a dose size perdefined displacement of the measuring means in the plug bore. While itis possible to vary the dose size by adjusting the position of the stopmeans, it is more convenient to provide a set of rotatable plugs perhousing, each having a plug bore adapted to measure a different dosesize. Convenient sizes for such a range of plugs include 0.5, 1.5, 2.5and 5 cc.

The reservoir of material to be dispensed may be sealed to the outerport of the inlet conduit by any convenient means. One constructionprovides a valve at one end of the reservoir biassed outwardly and aconstricting gland seating in the housing so that when the reservoir issecured to the housing, the gland lifts the valve off its seating withinthe reservoir allowing the flow of material into the inlet conduit.Another possible construction is one in which the reservoir contains novalve at all but the seating on the housing has a projecting pin whichpierces the top of the reservoir (which may have a thin area of wall forthis purpose) so releasing material into the outlet conduit. With thissecond construction it is convenient to provide a depression in the topof the reservoir and dispose a rubber or like washer about the housingpin so as to present a fluid-tight joint thereby minimising accidentalleakage of material.

One way in which the reservoir may be secured to the housing is byhinging sprung arms on the housing, which arms extend the length of thereservoir and bend over to grasp the bottom or top thereof. A second wayis by a bayonet catch joint in which bayonet buttons are provided on thehousing and bayonet eyelets in the reservoir. Yet another method is by ascrew thread connection, conveniently by providing an externallythreaded nozzle on the reservoir to mate with an internally threadedarea in the seating.

The reservoir is conveniently cylindrical and is made of a materialwhich will withstand pressures, usually of about 20 to lb./sq. in.,includes the reservoir for a prolonged period. The reservoir preferablycontains its own source of pressure conveniently provided by an internalpiston type pressure pack and the pressure may be developed by anyconvenient gas or gases, for example, nitrogen or carbon dioxide. It ison occasion more convenient to provide an independent source ofpressure, e.g. a large cylinder of nitrogen, in which case it isnecessary to provide an inlet valve to the internal pressure source inthe reservoir, to which a hand-pump may be fitted.

When the required number of doses have been administered and the dosingmechanism is no longer required, it may be put on one side pendingre-use. It is an advantageous feature of the mechanism of this inventionthat an apparatus incorporating the mechanism of this invention need notbe dismantled and cleansed thoroughly since the active ingredient in thematerial to be dispensed may be excluded from contact with air byprovidnig a cap for the discharge spout. If the reservoir is to bestored separately, a cap for the outer port of the inlet conduit may beproivded.

Brief description of the drawings The drawings show particular preferredembodiments of this invention in which:

FIGURE 1 shows a median longitudinal section through one embodiment ofmechanism according to this invention;

FIGURE 2 shows a transverse section through the embodiment shown inFIGURE 1 on line 11-11;

FIGURE 3 shows a median longitudinal section through part of anotherembodiment of mechanism according to this invention;

FIGURE 4 shows a side elevation view of a trigger mechanism for use withmechanism shown in FIGURE 4; and

FIGURE 5 shows a cross section of an aerosol can to which the mechanismshown in any of the previous figures may be attached.

Description of the preferred embodiments Referring first to FIGURE 1,there is shown a mechanism comprising a rotatable plug 1 located in ahole 2 inside a housing 3. Housing 3 has conduits on each side of hole2, on one side an inlet conduit 4 (shown in the drawing on the righthand side) and on the other side an outlet conduit 5 (shown on the lefthand side of the hole).

Plug 1 contains a bore 6 in which is located a free piston 7 which iscapable of longitudinal movement with the bore between limits defined bycirclips 8, 8'. The housing on the side of inlet conduit 4 extendsoutwardly to define a seating for a reservoir. As drawn, the seatingcomprises a seating chamber 9, closed by a gland 10 and aligned withinlet conduit 4 and bayonet catches 11, 11' for engagement with bayoneteyelets on the outer shell of a reservoir (not shown in this figure).The housing on the side of outlet conduit 5 extends to define adischarge spout 12 with a detachable barrel cap 13.

The tapering shape of plug 1 may be seen from FIG- URE 2 and circlip 8'can be seen in bore 6. The taper of the walls of plug 1 and the hole 2in housing 3 allows rotation of plug 1 in the vertical plane whilemaintaining contact between the inner walls of housing 3 and the wallsof rotatable plug 1 such that no material can leak therebetween.

Inlet conduit 4 will be seen to branch to form inlet port 4a, adjacentto outlet conduit 5, and inlet port 4b. Outlet conduit 5 branches toform outlet port 5a, adjacent to inlet port 4b, and an outlet port 5b.In the condition shown in FIGURE 1, piston 7 abuts circlip 8 and andinlet conduit 4 and bore 6 are filled with material. In operation, plug1 is rotated in a clockwise direction until bore 6 registers with ports5a and 4a with circlip 8 facing the latter. Material under pressure froma reservoir (not shown) forces piston 7 along bore 6 causing the dose ofmaterial in bore 6 to be discharge through outlet port 5a towards outletconduit 5, which in turn displaces a dose of equal volume of material tobe discharged from the end of the discharge spout 12. Rotation of plug 1in an anti-clockwise direction so that bore 6 registers at one end withinlet port 4b and at the other end with outlet port 5b causes, by themechanism described above, the discharge of another dose of material.Oscillation of the plug 1 in this manner enables repeated doses of thematerial to be discharged at a fast rate.

Another embodiment of the mechanism is shown in FIGURE 3 which showsonly the rotatable plug 1. The same reference numerals as those used inFIGURES 1 and 2 are employed here where applicable. Bore 6 is providedwith a centrally located hemi-spherical shaped diaphragm 14 of thinflexible material on each side of which there is mounted ahemi-spherical wire mesh support frame 15, 15'. The ends of diaphragm 14and wire meshes 15, 15 are supported in a ferrule 16 inset into one sideof plug 1 by screwing or crimping.

In operation, material passing through inlet conduit 4 displaces theflexible diaphragm 14 to abut a wire mesh (as drawn, diaphragm 14 wouldthen abut wire mesh 15'). Plug 1 is rotated in the manner beforementioned and the incoming material forces diaphragm 14 to abut mesh 15thereby displacing a dose equal to the volume contained between theextremities of movement of the diaphragm.

Turning now to FIGURE 4, this shows one form of simple mechanism forrotating the rotatable plug of the mechanism shown in FIGURE 1. Aneccentrically placed pin 33 on plug 1 is embraced by arms 34 of atrigger 35. Trigger 35 is hinged at or near the centre 36 of a hand grip37 which extends downwardly of the housing on the inlet side. Hand grip37 is so formed that part of trigger 35 may be pressed therein (thelower end of trigger 35 is shown in ghost outline in the lower part ofhand grip 37). It is apparent that reciprocal movement of trigger 35about hinge 36 effects a rotational movement on pin 34 therebyoscillating plug 1 through an arc of about 30-40.

FIGURE 5 shows a metallic aerosol can 40 having a flexible innercontainer 41 enclosing the material 42 to be dispensed upon whichpressure is exerted by means of compressed gas 43 in the remainder ofthe container. Material 42 passes through a valve device 44 into inletconduit 4 of the mechanism shown in FIGURE 1, the mechanism being heldin place to operate the valve 44 by the bayonet catches 11, 11' engagingwith bayonet eyelets at 45, 45 on can 40. The valve 44 ends in outletspout 46 which is sealed by gland 10.

We claim:

1. A mechanism for dispensing unit doses of a liquid, semi-liquid, orgaseous material comprising a housing having an opening therein, arotatable plug being positioned within and in sealing relationship withthe opening in said housing, said plug having a bore therethroughextending from one to the other surfaces of the opening, a flexiblediaphragm extending transversely across and being secured to said boreabout its periphery, a perforated stop member being disposed on eachside of said dia phragm, each of said stop members being secured withinand extending across said bore and being equally spaced from saiddiaphragm and the perforations therein permitting the material to passtherethrough, said housing forming an inlet conduit and an outletconduit, said inlet conduit extending from the exterior of said housingto the opening therein and said inlet conduit being branched to affordat least two inlet ports communicating with the opening, said outletconduit extending from the exterior of said housing to the openingtherein and said outlet conduit being branched to afford at least twooutlet ports communicating with the opening, each of said inlet portsbeing disposed in axial alignment across said opening with one of saidoutlet ports and said bore and said plug being arranged for selectivelyinterconnecting a pair of axially aligned said inlet and outlet ports assaid plug is rotated within said opening, a reservoir containing asource of material to be dispensed through said housing in detachablysealed engagement with said inlet conduit at the exterior of saidhousing, means for pressurizing the material within said reservoir, andsaid outlet conduit having a discharge opening on the exterior of saidhousing for discharging the material from said housing after its passagethrough said bore in said plug, and operating means for reciprocallyrotating said plug within said opening whereby each end of said bore isreciprocally positionable between one of said inlet ports and one ofsaid outlet ports and when one end of said bore is in communication withone said inlet port the other end thereof is in communication with onesaid outlet port so that the pressurized material being deliveredthrough said inlet port from said reservoir to said inlet ports foralternately supplying the material to the opposite ends of said bore,the supply of the material into said bore urging said flexible diaphragmagainst said perforated stop member on the opposite side thereof andsaid diaphragm thereby displacing the material on the opposite side ofsaid diaphragm outwardly from said bore through said outlet port intosaid outlet conduit, and the equal spacing between said diaphragm andsaid stop members affording uniform doses which are discharged from saidoutlet conduit during each reciprocal movement of said plug with saidbore therethrough alternating at its ends between said inlet and outletports.

2. A mechanism, as set forth in claim 1, wherein said stop members beingformed of wire mesh in a hemispherical shape with the concave surfacesthereof facing said diaphragm, and the volume of the space between saidstop members defining the volume of the uniform dose being provided bythe mechanism.

3. A mechanism, as set forth in claim 1, wherein a discharge spout issecured to the end of said outlet conduit at the end thereof at theexterior of said housing.

4. A mechanism, as set forth in claim 1, wherein a set ofinterchangeable said plugs being provided for the opening in saidhousing with the bores in said plugs containing an arrangement of saiddiaphragm and said stop members for measuring different unit doses ofthe material passing through said housing.

5. A mechanism, as set forth in claim 4, wherein said interchangebaleplugs being arranged for affording dose sizes of 0.5, 1.5, 2.5 and 5 cc.

6. A mechanism, as set forth in claim 1, wherein an outwardly biasedvalve located at the outlet end of said reservoir, and a constrictinggland seating being positioned on said housing at the outlet from saidreservoir to said inlet conduit for cooperating with said outwardlybiased valve for the supply of material into said inlet conduit.

7. A mechanism, as set forth in claim 1, wherein bayonet buttons beingfixed to said housing at the exterior thereof adjacent the inlet fromsaid reservoir to said inlet conduit, and bayonet eyelets on saidreservoir for interconnection with said bayonet buttons on said housingfor securing said reservoir thereto.

(References on following page) References Cited UNITED STATES PATENTSGoehring 222-249 Leonard 222219 X Wedeberg 22225O Bryant 222250 82,734,666 2/1956 Schmid 222250 2,969,632 1/1961 Carew et a1. 222219 X3,291,346 12/1966 Marrafiino.

5 SAMUEL F. COLEMAN, Primary Examiner US. Cl. X.R.

